Theorem 2.5 The entries of the QFIM for a pure parameterized state \(|\psi \rangle :=|\psi (\vec{x})\rangle \) 
can be obtained as [1]}, [2]}
\(\mathcal {F}_{ab}=4\mathrm {Re}(\langle \partial _{a}\psi |\partial _{b}\psi \rangle -\langle \partial _{a}\psi |\psi \rangle \langle \psi |\partial _{b}\psi \rangle ).\) 
